Prior to the advent of the instant invention, prosthodontic manufacturing systems have been extremely labor intensive and time consuming, requiring a considerable amount of skilled (artisan) labor to custom fit prosthodontics for each case. Examples of prior art prosthodontic systems include the 3M/ESPE Lava™ System zirconium CAD/CAM-CNC Crown and Bridge Coping/Infrastructure(Core), the Camlog Implant System 2-part titanium-zirconium Ti-Ceramic Implant Abutment, and the Atlantis (owned by Astra Tech, a U.S. subsidiary of Astra Zenecca) custom CAC/CAM titanium or zirconium abutments. The Lava™ System creates its crown or bridge Cores from green-stage zirconium via a CAD/CAM CNC milling process followed by an over-night chemical infiltration and heat shrink transformation (sintering) process. The Camlog Implant System, as well as some other implant systems, utilize a two-piece standard product line implant abutment comprised of an upper manufactured sintered ceramic (zirconium) portion that requires subsequent custom modification by dental lab technicians in the field and a lower metal portion that affixes to the implant in the location in which a tooth replacement is necessary in the patient's mouth. The ceramic portion of the abutment, which is cement-bonded to the metal portion after the ceramic portion requires modification in the dental lab prior to beginning the construction of the crown coping (Core). The modified implant abutment affixed to a laboratory analog (implant duplicate) in the master stone laboratory model serve as the prepared tooth stump base for fabrication of a custom crown and bridge Core, such as a Lava™ crown and bridge coping/infrastructure (Core). The Atlantis system utilizes optically/laser scanned implant orientation information from a laboratory master stone model or patient to create a custom abutment from CAD/CAM instructions. A crown and bridge coping (Core) can then be made for the Atlantis or Camlog abutments conventionally by a lost wax artisan method (results in a metal crown and bridge Core) or from a separately scanned and CAD file generated CAM milling (results in a ceramic crown and bridge Core). It is noted that ceramic crown copings (Cores) can also be fabricated in an artisan method from built-up powder as in the Vita/Vident Inceram® zirconium System. It is noted also, all all-ceramic crown systems at present require some type of ceramic base coping/infrastructure (Core) and subsequent porcelain overlay to achieve the desired contours of the tooth that is being replaced. But in all cases, by prior art, Implant abutments must be fabricated before Crown and Bridge Cores can be designed and fabricated, and finished Crowns can only be fabricated after the completion of the Core and its geometry is known by post fabrication inspection.
In the conventional system, when a patient requires a tooth replacement, a three-dimensional stone model of the patient's mouth is prepared from a master impression. If a two-piece abutment such as the Camlog Implant System's Ti-Ceramic Abutment described above is to be utilized, a lab technician will use the stone lab model of the patient's mouth to fit and manually modify the sintered zirconium portion of the two-part abutment (or coronal portion of any all metal abutment) and then affix it to the metal portion of the abutment into the appropriate implant analog location in the model. The ceramic portion of the abutment is shaped so it is appropriate for the location and orientation in which it will best support the final crown positioned within the patient's mouth. Once the ceramic portion of the abutment is modified to its final shape, the abutment, which is located in the model, is scanned. Using data from the scan about the shape and orientation of the abutment, as well as the existing teeth surrounding the position of the abutment, the necessary shape of a crown coping (Core) is determined and the crown coping (Core) is manufactured. In the context of the Lava™ System, a Computer Numeric Control (CNC) milling machine is utilized to manufacture the coping/infrastructure (Core) by milling a green-stage zirconium Lava™ block into a coping/infrastructure (Core) that is then heat treated. Once the coping is completed, and built-up with porcelain to resemble a natural tooth, the entire piece (coping and abutment) is ready for placement in the patient's mouth. The crown coping/crown may be cemented conventionally (like any crown to a tooth) to the installed abutment.
The prior art system described above is very time consuming, as it requires a considerable amount of labor and time to modify the abutment and then separately manufacture the coping (Core) based upon the shape of the modified abutment, and then start on another unrelated process to build the Core to its final geometry with porcelain. In some cases, the ceramic portion of the abutment requires considerable modification due to its orientation within the patient's mouth such that a relatively small surface of the abutment remains for mounting of the coping (Core). It is noted that a ceramic infiltrated sintered abutment is extremely hard to cut compared to green stage zirconium material. In addition, the prior art system results in substantial waste of materials as the ceramic abutment and the coping (Core) are manufactured independently and/or by different processes and/or materials. Certainty of final geometry, size and precision is lost if shaping is accomplished in the green stage zirconium, because unpredictable shrinkage often exceeding 20% will result in subsequent required heat shrink transformation treatments. Therefore, it would be beneficial to provide a system for simultaneously manufacturing a custom dental crown coping/infrastructure (Core) and implant abutment (or ceramic portion of the abutment if two piece) to reduce the amount of labor, time and materials.
As the conventional system for designing dental restorations described above requires that a dental restoration be designed (and built) in a derivative, linear manner from the ground up, i.e. first design the abutment, then design the coping (Core) to fit the abutment, manufacturing processes and systems have been extremely limited. Improvements in technology have been interspersed throughout the process at various levels to replace certain functions, but the system as a whole remains relatively unchanged and inefficient. In many cases, the technology has increased the overall production time for a dental restoration, because it is being added to a manufacturing process rather than designed as part of a manufacturing process and/or supporting the manufacturing process. Mass production has generally occurred at the pre-made prosthetic component level rather at the end product production level. As such manufacturers will mass-produce abutments of several shapes and/or sizes so that a suitable piece may be selected for the particular situation and require minimal modification. As each patient's mouth is different, every dental restoration is unique. Thus, having a finite number of options of shapes and sizes of mass-produced abutments requires that the abutment be modified for the particular application (as is described above). Even the Atlantis custom implant abutment starts the process with an inventory of individual partially-machined implant brand-specific blanks, to produce final custom abutments. Even though the Atlantis custom implant abutment is the product of a modern CAD/CAM design and milling process, it still has no coordinated follow-on Core process. Once modified, the abutment must be scanned and a custom coping (Core) may be machined by another system. This conventional system is best described as a custom mass-production system, as certain parts may be mass produced to make customization easier, but those parts must still be modified or customized before they can be utilized. Therefore, it would be beneficial to provide a system and method for Mass Custom Manufacturing of dental restorations and/or components thereof.
Furthermore, each component of a restoration in the custom mass-production system of the prior art discussed above is still designed and made individually. The prior art custom mass-production system is really a combination of multiple systems, as opposed to a single system of production. For example, once an abutment is modified by a dental technician and scanned, the data from the scan of the abutment is used to manufacture a coping (Core) that fits the modified abutment. The data file used to machine the coping (Core) is no longer used. And it has not been archived in any manner to feed some follow-up production process. In the case of modern press ceramic application method, a wax-up of the final restoration is made on top of the coping (Core), and the entire unit is sprued and invested in a lost wax burnout method for later press packing and baking of ceramic material. The wax is melted out of the mold and the mold is used to press the porcelain veneer material to make the final shape of the restoration. It is noted porcelain may also be layered and baked in an artisan method also to achieve a final all-ceramic restoration, alternative to the press ceramic method. But the point to be made is in prior art, the coping (Core) itself is always designed and manufactured individually without any direct subsequent relation to follow along processes. The coping (Core) will be designed by a CAD user, and the CAD file will be sent to a CAM operator to manufacture the piece that has been designed, and all processes to follow are independent of the CAD/CAM process of making the coping (Core). In some instances, the CAD user will design a piece that is impossible for the CAM to mill, and all subsequent processes are thereby totally thwarted until the Core mill is resolved. In prior art it is entirely possible that all components all the way back to the implant abutment, may have to be remade, because of the failure of designing the first component to the dimensional requirements of the actual condition in the mouth and on the master model. It is noted that each process, although technologically embellished, in prior art is driven by individual and non-interrelated design, engineering and manufacturing processes. Therefore, it would be beneficial to provide a system and method for mass custom production (a Mass Custom Manufacturing System) that provides increased efficiencies over the custom mass-production system of the prior art.